1. Field
The present invention relates generally to semiconductor manufacturing and, more particularly, to apparatus for defining regions of process exclusion and of process performance in a process chamber for manufacturing semiconductor wafers, wherein a process such as etching is excluded from a central area of the wafers, and an etching process is allowed to be performed on the wafer outside of the central area on an edge environ of the wafer.
2. Description of the Related Art
Vacuum processing chambers have been used for etching materials from substrates and for deposition of materials onto substrates. The substrates have been semiconductor wafers, for example. In general, accurate processing (and thus high yields of devices) is expected to occur in a central area of the wafer. Numerous difficulties are experienced in attempting to accurately process the wafer on a portion of a top, or upper, surface of the wafer, wherein that portion is between the central area and a peripheral edge of the wafer that surrounds the central area. Such difficulties are significant enough that an “edge exclusion area” has been defined between the central area and that edge of the wafer surrounding the central area of the upper surface. No attempt is made to provide acceptable devices in that edge exclusion area.
Additionally, during the desired processing of the central area, undesired deposits, materials, or process-by-products (collectively “undesired materials”), accumulate or result on the edge exclusion area of the upper surface of the wafer, and on an edge area around the peripheral edge of the wafer, and below the edge area on a bottom area of an opposite (bottom) surface of the wafer. Those three areas are not to be processed to form devices. The edge exclusion area, the edge area, and the bottom area are referred to collectively as the “edge environ”. These undesired materials may generally accumulate on the edge environ. The accumulation is so extensive that the desired processing of the central area must be interrupted because, in general, it is desired to keep the edge environ substantially clean so as to avoid flaking of material particulates that may redeposit back onto the active device regions on the upper surface of the wafer. Such flaking can occur during any number of wafer handling or transport operations. Thus, it is a general desire that the edge environ be periodically cleaned (e.g., etched) or monitored for cleaning (i.e., etching) during the numerous processing operations used to fabricate integrated circuit device chips, from the processed wafers. The desired processing of the central area has been interrupted to perform such periodic cleaning in an attempt to remove the undesired materials from the edge environ, e.g. from the entire edge environ, and e.g., to perform such removal without damaging the devices.
However, as attempts are made to more accurately process the wafers, the specifications for such periodic cleaning are subject to change, e.g., from one batch of wafers to another batch of wafers. For example, from batch to batch the specifications may define different portions of the edge environ to be subjected to the cleaning process. Prior apparatus for such cleaning has not been readily adaptable to such changed specifications, such that problems have been experienced in attempts to efficiently perform more accurate removal of the undesired materials from every batch of wafers.
In view of the foregoing, what is needed is apparatus for edge environ cleaning that is readily adaptable to such changed specifications. What is also needed is apparatus that is configured to efficiently perform more accurate removal of the undesired materials on every batch of wafers even though the specifications for cleaning each batch may be changed from batch to batch. A further need is to rapidly configure apparatus for the removal of the undesired materials from the edge environ, the configuring conforming to a wide variety of specifications for such removal, by which the apparatus is rendered capable of removing the undesired materials from only a currently-specified portion of the edge environ and is capable of not damaging the central area. Also, despite such configuring, use of the configured apparatus should result in accurate (e.g., uniform) removal of the undesired materials from the entire currently-specified portion of the edge environ without removing materials from or otherwise damaging the central area.